project(PNG)

set(PNGLIB_MAJOR 1)
set(PNGLIB_MINOR 2)
set(PNGLIB_RELEASE 15)
set(PNGLIB_NAME libpng${PNGLIB_MAJOR}${PNGLIB_MINOR})
set(PNGLIB_VERSION ${PNGLIB_MAJOR}.${PNGLIB_MINOR}.${PNGLIB_RELEASE})

# needed packages
find_package(ZLIB REQUIRED)
if(NOT WIN32)
 find_library(M_LIBRARY
     NAMES m
     PATHS /usr/lib /usr/local/lib
 )
 if(NOT M_LIBRARY)
   message(STATUS "math library 'libm' not found - floating point support disabled")
 endif(NOT M_LIBRARY)
else(NOT WIN32)
 # not needed on windows
 set(M_LIBRARY "")
endif(NOT WIN32)


# COMMAND LINE OPTIONS
option(PNG_SHARED "Build shared lib" YES)
option(PNG_TESTS  "Build pngtest" YES)
option(PNG_NO_CONSOLE_IO "FIXME" YES)
option(PNG_NO_STDIO      "FIXME" YES)
option(PNG_DEBUG         "Build with debug output" YES)
option(PNGARG            "FIXME" YES)
#TODO:
# PNG_CONSOLE_IO_SUPPORTED

# maybe needs improving, but currently I don't know when we can enable what :)
set(png_asm_tmp "OFF")
if(NOT WIN32)
 find_program(uname_executable NAMES uname PATHS /bin /usr/bin /usr/local/bin)
 if(uname_executable)
   EXEC_PROGRAM(${uname_executable} ARGS --machine OUTPUT_VARIABLE uname_output)
   if("uname_output" MATCHES "^.*i[1-9]86.*$")
      set(png_asm_tmp "ON")
   else("uname_output" MATCHES "^.*i[1-9]86.*$")
      set(png_asm_tmp "OFF")
   endif("uname_output" MATCHES "^.*i[1-9]86.*$")
 endif(uname_executable)
endif(NOT WIN32)

option(PNG_MMX "Use MMX assembler code (x86 only)" ${png_asm_tmp})

# SET LIBNAME
# msvc does not append 'lib' - do it here to have consistent name
if(MSVC)
 set(PNG_LIB_NAME lib)
endif(MSVC)
set(PNG_LIB_NAME ${PNG_LIB_NAME}png${PNGLIB_MAJOR}${PNGLIB_MINOR})

# to distinguish between debug and release lib
set(CMAKE_DEBUG_POSTFIX "d")

# append _static to static lib
if(NOT PNG_SHARED)
 set(PNG_LIB_NAME ${PNG_LIB_NAME}_static)
endif(NOT PNG_SHARED)


# OUR SOURCES
set(libpng_sources
 png.h
 pngconf.h
 png.c
 pngerror.c
 pngget.c
 pngmem.c
 pngpread.c
 pngread.c
 pngrio.c
 pngrtran.c
 pngrutil.c
 pngset.c
 pngtrans.c
 pngwio.c
 pngwrite.c
 pngwtran.c
 pngwutil.c
)
set(pngtest_sources
       pngtest.c
)


# SOME NEEDED DEFINITIONS
add_definitions(-DZLIB_DLL)

if(MSVC)
 add_definitions(-DPNG_USE_PNGVCRD -DPNG_NO_MODULEDEF -D_CRT_SECURE_NO_DEPRECATE)
 set(libpng_sources ${libpng_sources}
         pngvcrd.c
 )
else(MSVC)
 add_definitions(-DPNG_USE_PNGGCCRD)
 set(libpng_sources ${libpng_sources}
         pnggccrd.c
 )
endif(MSVC)

if(NOT MSVC)
 if(NOT PNG_MMX)
   add_definitions(-DLIBPNG_NO_MMX)
   add_definitions(-DPNG_NO_MMX_CODE)
 endif(NOT PNG_MMX)
else(NOT MSVC)
 if(PNG_MMX)
 # maybe add this to pngconf.h ?
 add_definitions(-DPNG_MMX_CODE_SUPPORTED)
 endif(PNG_MMX)
endif(NOT MSVC)


if(PNG_CONSOLE_IO_SUPPORTED)
 add_definitions(-DPNG_CONSOLE_IO_SUPPORTED)
endif(PNG_CONSOLE_IO_SUPPORTED)

if(PNG_NO_CONSOLE_IO)
 add_definitions(-DPNG_NO_CONSOLE_IO)
endif(PNG_NO_CONSOLE_IO)

if(PNG_NO_STDIO)
 add_definitions(-DPNG_NO_STDIO)
endif(PNG_NO_STDIO)

if(PNG_DEBUG)
 add_definitions(-DPNG_DEBUG)
endif(PNG_DEBUG)

if(NOT M_LIBRARY)
 add_definitions(-DPNG_NO_FLOATING_POINT_SUPPORTED)
endif(NOT M_LIBRARY)

# NOW BUILD OUR TARGET
include_directories(${PNG_SOURCE_DIR} ${ZLIB_INCLUDE_DIR})

if(PNG_SHARED)
 add_library(${PNG_LIB_NAME} SHARED ${libpng_sources})
else(PNG_SHARED)
 add_library(STATIC ${libpng_sources})
endif(PNG_SHARED)

target_link_libraries(${PNG_LIB_NAME} ${ZLIB_LIBRARY} ${M_LIBRARY})
if(PNG_SHARED AND WIN32)
 set_target_properties(${PNG_LIB_NAME} PROPERTIES DEFINE_SYMBOL PNG_BUILD_DLL)
endif(PNG_SHARED AND WIN32)

if(PNG_TESTS)
# does not work with msvc due to png_lib_ver issue
 add_executable(pngtest ${pngtest_sources})
 target_link_libraries(pngtest ${PNG_LIB_NAME})
#  add_test(pngtest ${PNG_SOURCE_DIR}/pngtest.png)
endif(PNG_TESTS)


# CREATE PKGCONFIG FILES
# we use the same files like ./configure, so we have to set its vars
set(prefix      ${CMAKE_INSTALL_PREFIX}/bin)
set(exec_prefix ${CMAKE_INSTALL_PREFIX}/bin)
set(libdir      ${CMAKE_INSTALL_PREFIX}/lib)
set(includedir  ${CMAKE_INSTALL_PREFIX}/include)

configure_file(${PNG_SOURCE_DIR}/scripts/libpng.pc.in ${PNG_BINARY_DIR}/libpng.pc)
configure_file(${PNG_SOURCE_DIR}/scripts/libpng-config.in ${PNG_BINARY_DIR}/libpng-config)
configure_file(${PNG_SOURCE_DIR}/scripts/libpng.pc.in ${PNG_BINARY_DIR}/${PNGLIB_NAME}.pc)
configure_file(${PNG_SOURCE_DIR}/scripts/libpng-config.in ${PNG_BINARY_DIR}/${PNGLIB_NAME}-config)

# INSTALL
install_targets(/lib ${PNG_LIB_NAME})
install(FILES png.h pngconf.h                 DESTINATION include)
install(FILES png.h pngconf.h                 DESTINATION include/${PNGLIB_NAME})
install(FILES libpng.3 libpngpf.3             DESTINATION man/man3)
install(FILES ${PNG_BINARY_DIR}/libpng.pc     DESTINATION lib/pkgconfig)
install(FILES ${PNG_BINARY_DIR}/libpng-config DESTINATION bin)
install(FILES ${PNG_BINARY_DIR}/${PNGLIB_NAME}.pc     DESTINATION lib/pkgconfig)
install(FILES ${PNG_BINARY_DIR}/${PNGLIB_NAME}-config DESTINATION bin)

# what's with libpng.txt and all the extra files?


# UNINSTALL
# do we need this?


# DIST
# do we need this?

# to create msvc import lib for mingw compiled shared lib
# pexports libpng.dll > libpng.def
# lib /def:libpng.def /machine:x86